Fuel injection system



Sept. 20, 1960 A. D. MCDUFFIE 2,953,331

FUEL INJECTION SYSTEM Filed May '7. 1958 Z'Sheets-Sheet 1 ALTURA/Ey Sept. 20, 1960 A. D. MCDUFFIE i 2,953,361 FUEL. INJECTION SYSTEM 2 sheets-sheet 2 Filed May 7, 1958 FUEL 7A NA Qi/Q .from its respective ends.

nited States Patent FUEL INJECTION SYSTEM Filed May 7, 1958, Ser. No. 733,718

`6 Claims. (Cl. 261-2'3) The present invention relates to a fuel injection system in which the quantity of fuel supplied to the individual cylinders of the engine is determined by mass air flow. More specifically, the present fuel system embodies a ful distributing device in which the mass air iiow metered fuel is delivered to the individual engine cylinders in quantities timed to engine speed.

While the mass air flow control system may be of any well known type, the present invention has been illustrated with the system shown in copending application Serial No. 634,915 McDue, filed January 18, 1957 on which Patent No. 2,893,711 issued July 7, 1959. The mechanism for distributing timed charges of fuel to the individual cylinders of the engine is preferably of the shuttle piston type which has been uniquely combined with a mass air -ow controlled system. In this type of distributor a reciprocating piston is employed which alternately supplies fuel to one-half the engines cylinders By alternately supplying fuel to the respectvie ends of the shuttle piston, one end is charged with fuel while the other is supplying its cylinders with cycle lbeing reversed in timed relation to engine speed.

The present invention in uniquely combining mass air flow fuel metering and shuttle piston timed fuel distributing has resulted in `a fuel injection system which more nearly meets the standards of economy of manulfacture and preciseness of fuel metering than has heretofore been realized.

Other objects and advantages of the present invention will be apparent from a perusal of the detailed description which follows:

vIn the drawings:

Figures 1, la and lb are sectional invention; and

Figure 2 is an enlargement of the secondary throttle switch mechanism.

views of the subject Referring to the drawings, an Iair induction casing is shown at 10 and Aincludes an air induction passage 12 having a pair of parallel related passages 14 and 16. The smaller passage 14 includes a venturi 18 formed -therein and continuously supplies air therethrough in accordance with the position of a primary throttle valve 20. Valve 20 is disposed Within induction casing 10 posteriorly of passages 14 and 16.v

An annular chamber or piezometer ring 22 is formed Patented Sept. 20, 1960 disposed in each intake passage -32 proximate the cylint der intake valve 38 for supplying metered and timed quantities of fuel to the cylinder.

In the event .the subject system is maintained under a superatmospheric pressure, nozzles 36 may be of the pressure responsive type in which a spring biased valve 40 will enable the system to be pressurized. Valve 40 will open when the fuel pressure exceeds a predetermined minimum-value.

While secondary throttle 28 may be controlled in any desired manner, in the -aforenoted McDuiiie fuel metering system with which the present invention has been illustrated it is controlled by a servo mechanism 42. Servo 42 includes a casing 43 peripherally supporting a diaphragm 44 having a control rod 46 centrally connected thereto and articulated at its other end to a throttle valve lever 48. A spring is disposed within servo casing 43 and normally biases throttle 28 in a closed position as shown. Servo chamber 52 communicates with a conduit 54 which is 'adapted to be supplied with a vacuum force through a throttle controlled switching mechanism 56.

Mechanism 56 includes a casing -58 peripherally supporting a diaphragm 60. A valve member 62 is fixed to diaphragm 60 and is adapted to control the admission of vacuum from a supply conduit 64 to conduit 54. Vacuum from conduit 64 is exposed to both sides of diaphragm 60, the upper side being supplied by a restricted passage 66. Due to the greater effective area on the upper side of the diaphragm, valve 62 is maintained in a closed position. The upper diaphragm chamber 68, deiined by diaphragm 60 and cover 70, is adapted to be vented to the atmosphere through a port 72 controlled by a primary throttle actuated lever 74 and valve 76. Thus, when the primary throttle 20 is opened beyond a predetermined amount, an eccentric lever 78 coupled to throttle 20 will rotate lever 74 in a clockwise direction raising valve 76 through tension spring 80 and venting chamber `68 to the atmosphere. As a consequence, the pressure diiferential acting on diaphragm 60 will open valve 62 admitting the vacuum to servo 42 to snap open secondary throttle 2S.

As described in the aforenote-d McDufIie application,

y the Ifuel metering mechanism 26 includes a pair of diaphragms 82 and 84, respectively, peripherally clamped between a central casing 86 and end casings 88 and 90. A U-shaped yoke member 92 pivotally mounted within casing 86 includes an arm 94 lixed to diaphragm 82 and an arm 96 fixed to diaphragm 84. Diaphragm 82 coacts with casing 88 to form a chamber 98 supplied with venturi vacuum by conduit 24. Chamber 100 deiined by diaphragm 82 and casing 86 is vented to the atmosphere through a port 102. Thus, ythe position of the diaphragm 82 is varied in accordance with the vacuum in casing 10 in open communication with the throat of Induction casing 10 communicates Awith -a plenum or force extant in piezometer ring 22.

As best seen in Figure 1b, yoke 92 includes a partially hollow cross member 97 which coacts with a member 99 lhaving a ball section 101 at one end. The other end of member 99 has a ball section 103 coacting with a supporting arm extending from casing 86. Member 99 permits pivotal movement of yoke member 92 while at the same time restraining the latter against lateral displacement relative to casing 86.

Yoke arm 96 includes a metering valve 104 fixed to its free end for movement therewith. Metering valve 104 is described in detail in copending application Serial No. 726,188 Scoville.

Fuel under substantially constant pressure is supplied from a reservoir or tank 106 by a pump 108 to conduit 110. Conduit 115i' supplies the constant pressure fuel to a passage 112 in casingl 90y of metering mechanism 26.

Diaphragm 84 respectively coacts with casings 86 and 910 to define fuel chambers 114 and 116. Fuel -is supplied to chamber 114 in accordance with the posit-ion of valve memberv 104' which in turn is controlled by yoke member 92. Fuel chamber 114 includes an: outlet conduit 11S- through which an orificed passage 120 supplies fuel to diaphragm chamber 116 and distributor supply passage 122. By thusV connecting fuel chambers 114 `and 1716- through an orificed passage 120, a fuel pressure differential is created across :thel diaphragm 84 which is proportional to fuel iiow and which in turn modifies the position of the yoke member 92 in accordance therewith- Thus, the quantity of metered fuel supplied to conduit 122 i`sy proportional to mass air iiow as modified by fuelV ow.

The metered fuel from conduit 122 is supplied through branch passages 124V and 126 to a fuel distributing mechanism indicated generally at 130.. Fuel distributor 130 comprises a rotary distributor member 132 disposedv in casing 134 and adaptedv to be driven by a shaft 136 in proportion to engine speed. Rotary distributor 132 includes a cylindrical opening 138 within which a shuttle piston 140 is. slidably mounted. Casings 142 and 144 coact with casing 134 to define fuel cavities 146 and 148 with distributor opening 13S. Cavities 146 and 148 are communicated with fuel passages 150 and 152. Metered fuel from branch passage 124 is supplied to chamber 154 from whence -it is delivered to interconnected annular chamber 156 and 15d. Rotary distributor passage 152l is adapted to communicate with annular chamber 156 while rotary distributor' passage 15%' is adapted to communicate through passage 161i with annular chamber 15S'.

As distributor 132 is rotated, metered fuel under pressure wil-l alternately be supplied to the respective distributor cavities146 `and 148. At the time fuel is being supplied to one of said cavities the pressure of said fuel causes the shuttle piston 140 to be shifted to pump a metered charge of fuel from the other cavity to the appropriate nozzle supply conduit 162. The amount of travel of shuttle piston 144i and hence the quantity of the timed. fuel charge is determined by the distance between a fixed stop 164 and an adjustable stop 166.

With the parts in the position shown in Figure la, fuel under pressure is supplied from annular chamber 154 to distributor passage 152 and cavity 14S forcing shuttle piston 141i to the left where he fuel in cavity 146 is forced out through distributor passage 151) where it ows through passage 168 to conduit 162. As the distributor 132 is rotated this process is reversed and the shuttle piston moved in the opposite direction to supply fuel to another fuel nozzle from cavity 14S.

The adjustable shuttle piston stop 166 is slidably mounted in casing opening 171i and projects within a chamber 172 formed in casing 174 and enclosed at one end by a diaphragm member 176. Metered fuel under pressure is supplied to chamber 172 by branch passage 126.

A cam member 17S is centrally fixed to diaphragm plug 1510. Cam member 178 is adapted to coact with a follower member 12 mounted on `adjustable stop 166. TheV fuel pressure in chamber 172 acts upon diaphragm 176 in opposition tothe substantially constant force of the fuel pressure acting on diaphragm 183 in casing chamber 184 which is supplied by conduit 186. Thus, asV the quantity and pressure of fuel supplied by the metering mechanism 26 is increased with mass air ow, cam 17S is moved to the left whereby adjustable stop 166 is simil-arly so moved by the pressure of fuel in cavity 146 thereby increasing `the quantity of fuel discharged by shuttle piston 141i during each reciprocation thereofreflecting the increased need of the engine for fuel.

The unit fuel pressure in chamber 134V is greater than that` in chamber 172, therefore, it is necessary that` the effective area of diaphragm 183 be sufiiciently less than 4 that of diaphragm 176 yto insure under all air flow conditions the force acting onk the latter diaphragm determines the position of cam 178. By utilizing fuel pressure on the input side of metering mechanism 26 to `oppose metered fuel pressure, it is assured only pressure changes due in mass air fiow will affect the position of cam 178.

I claim:

l. A charge forming device for an internal combustion engine comprising an air inductionI passage, throttle means for controlling the flow of air through said induction passage, venturi' means in said inductionpassage, a plurality of intake passages adapted to communicate said induction passage with the individual cylinders of the engine, a fuel nozzle in each of said intake passages, a source of fuel under pressure, a fuel metering valve, means responsive to the mass of air flow through said venturi means for controlling said metering valve, and a fuel distributor intermediate said metering valve and said nozzles for fuel charges to-said' nozzles in timed: relation to engine speed, said distributor including means responsive to the metered fuel pressure for varying the magnitude ofv said fuel charges.

2. A charge forming devicefor an internal combustion engine comprising an air induction passage, throttle means for controlling the iiow of `air through said induction passage, venturi means in said induction passage, a plurality of intake passages adapted to communicate said induction passage with the individual cylinders of the engine, a fuel nozzle in each of said intake passages, a source of fuel under pressure, a fuel metering valve, means responsive to the mass of air iiow through said venturi means for controlling said metering valve, and a fuel distributor intermediate said metering valve and said nozzles for distributing fuel to said nozzles in timed relation to engine speed, -said fuel distributor comprisinga -rotary distributor member driven in timed relation to engine speed, -a shuttle piston member reciprocably mounted in said member,v a fixed stop and an adjustable stop for controlling the reciprocable movement of said piston, fuel cavities defined by the respective ends of said piston and said rotary distributor member, passage means for alternately communicating said fuel cavities with said metering valve and said fuel nozzles whereby reciprocation of said piston will supply a timed quantity of fuel to each nozzle, a chamber, passage means communicating said metering valveV with said chamber, said adjustable stop including an end projecting within said chamber,` cam means in said chamber adapted to coact with said end of said adjustable stop to vary the axial position thereof, and diaphragm means in said chamber operatively connected to said cam and adapted to vary the position thereof in accordance with the quantity of fuel supplied by said metering valve.

3. A charge forming device for an internal combustion engine comprising an air induction passage, throttle means for controlling the ow of air through said induction passage, venturi means in. said induction passage, a plurality of intake passages adapted -to communicate said induction passage with the individual cylinders of the engine, a fuel nozzle in each of said intake passages, a source of fuel under pressure, a fuel metering valve, means responsive to the mass of air flow through said venturi means for controlling said metering valve, and a fuel distributor intermediate said metering valve and said nozzles for distributing fuel to said nozzles in timedy relation to engine speed, said fuel distributor comprising a rotary distributor member driven in timed relation to engine speed, a shuttle piston member reciprocably mounted in said member, a fixed stop and an adjustable stop for controlling the reciprocable movement of said piston, fuel cavities defined by the respective ends of said piston and said rotary distributor member, passage means for alternately communicating said fuel cavities with said metering valve and said fuel nozzles whereby reciprocation. of said piston will supply a timed quantity of fuel to each nozzle, a chamber, passage means communicating said metering valve with said chamber, said adjustable stop including an end projecting Within said chamber, cam means in said chamber adapted to coact with said end of said adjustable stop to vary the axial position thereof, and means in said chamber operatively connected to said cam and adapted to vary the position thereof in accordance With the quantity of fuel supplied by said metering valve.

4. A charge forming device for an internal combustion engine comprising an air induction passage, throttle means for controlling the ow of air through said induction passage, venturi means in said induction passage, a plurality of intake passages adapted to communicate said induction passage with the individual cylinders of the engine, a fuel nozzle in each of said intake passages, a source of fuel under pressure, a fuel metering valve, means responsive to the mass of air flow through said venturi means for controlling said metering valve, and a fuel distributor intermediate said metering valve and said nozzles for distributing fuel to said nozzles in timed relation to engine speed, said fuel distributor comprising a rotary distributor member driven in timed relation to engine speed, a shuttle piston member reciprocably mounted in said member, a fixed stop and an adjustable stop for controlling the reciprocable movement of said piston, fuel cavities defined by the respective ends of said piston and said rotary distributor member, passage means for alternately communicating said fuel cavities with said metering valve and said fuel nozzles whereby reciprocation of Vsaid vpiston Will supply a timed quantity of fuel to each nozzle, a chamber, passage means communicating said metering valve with said chamber, said adjustable stop including an end projecting within said chamber, cam means in said chamber adapted to coact with said end of said adjustable stop to vary the axial position thereof, and diaphragm means responsive to the metered fuel pressure for varying the position of said cam relative to the adjustable stop.

5. A charge forming device for an internal combustion engine comprising an air induction passage, throttle means for controlling the flow of air through said induction passage, venturi means in said induction passage, a plurality of intake passages adapted to communicate said induction passage with the individual cylinders of the engine, a fuel nozzle in each of said intake passages, a source of fuel under pressure, a fuel metering valve, means responsive to the mass of air How through said venturi means for controlling said metering valve, and a fuel distributor intermediate said metering valve and said nozzles for distributing fuel to said nozzles in timed relation to engine speed, said fuel distributor comprising a rotary distributor member driven in timed relation to engine speed, a shuttle piston member reciprococably mounted in said member, a xed stop and an adjustable stop for controlling the reciprocable movement of said piston, fuel cavities defined by the respective ends of said piston and said rotary distributor member, passage means for alternately communicating said fuel cavities with said metering valve and said fuel nozzles whereby reciprocation of said piston will supply a timed quantity of fuel to each nozzle, a chamber, passage means communicating said metering valve with said chamber, said adjustable stop including an end projecting Within said chamber, cam means in said chamber adapted to coact with said end of said adjustable stop to vary the axial position thereof, first diaphragm means in said chamber operatively connected to said cam and adapted to vary the position thereof in accordance with metered fuel pressure, second diaphragm means operatively connected to said cam, and conduit means communicating said source of fuel under pressure with said second diaphragm to oppose the force of the metered fuel pressure.

6. A charge forming device as set forth in claim 5 in which the area of said second diaphragm means is less than that of the first diaphragm means.

References Cited in the le of this patent i UNITED STATES PATENTS 2,626,789 Mock Jan. 27, 1953 2,788,082 Vanderpoel Apr. 9, 1957 2,837,074 Ransom June 3, 1958 

